Final answer:
The cost that could be represented by a line parallel to the horizontal axis is employees who are paid $10 per hour and guaranteed a minimum weekly wage of $200.
Step-by-step explanation:
A cost that could be represented by a line parallel to the horizontal axis is employees who are paid $10 per hour and guaranteed a minimum weekly wage of $200. This is because the cost remains constant regardless of the volume of activity. For example, if no hours are worked, the cost would still be $200.